The present invention relates to the field of modular, ready-to-assemble furniture, and more specifically, a frame assembly for securing together a group of modular furniture parts to form a completed furniture piece.
Furniture pieces are typically manufactured and assembled at a factory and then shipped as a complete unit to a distributor or customer. The sections of the furniture piece are typically joined together using bolts that extend through predrilled holes in wooden or metal parts of the sections. Upholstery is used to cover the furniture sections, including the bolts and wooden or metal parts of the sections. The completed furniture piece is typically too heavy to be handled by a single individual and too large to be maneuvered through some doorways and stairwells. As a result, customers may limit the furniture that they choose to purchase or may object to additional charges required for third-party delivery of the furniture. In addition, it is difficult to efficiently pack assembled furniture pieces due to their size, shape and the fragility of the upholstered surfaces. Damage to any portion of the furniture piece typically requires the entire furniture piece to be shipped to a factory for repair.
One approach to this problem has been through the use of ready-to-assemble (RTA) furniture that provides increased options for storage, delivery and assembly of the furniture. For instance, U.S. Pat. No. 5,338,095 to Laughlin et al. discloses a furniture piece that relies on interlocking frame members to secure the modular sections together. The interlocking joints are designed to be easy to assemble. In one instance, a pair of combined wedge and parallelepiped shaped sockets 64 defined at the lower ends of a pair of vertical side members 72 of a backrest member 26 allow the backrest member to be secured to a pair of rail members 50, as shown in FIG. 3. Despite the ease of assembly, the furniture disclosed by Laughlin, and other conventional RTA furniture, can suffer from looseness in the fit between the modular sections that results in instability. For example, a looseness in fit due to repetitive loading can result in wobble or rocking of the backrest relative to the base of the furniture piece. Laughlin attempts to solve this problem with the addition of a pair of thumbscrews 96 that secure the backrest member to respective wing portions 100 of the seat. However, a pair of unsightly flaps in the upholstery are necessary to secure the thumbscrews and the thumbscrews require the presence of the wing portions for attachment, thereby limiting aesthetic design variations.
Attempts have been made to eliminate the problem of instability through other variations in the method of assembling, or fastening, the modular pieces together. For instance, U.S. Pat. No. 5,551,757 to Glover discloses a fastening system for RTA furniture. The fastening system employs side-support rails secured to the arm sections of the seat which allow either a seat platform or a foldout bed platform to be secured within the furniture piece. A pair of hooks are mounted to a back section and the back section is connected to the side-support rails and between a pair of armrests by mounting the hooks on a pair of engagement pins of the side-support rails. The back section is further secured using hard bolts 88 that are fed through the back section and into the armrests, as shown in FIG. 2. Although the fastening system of the Glover patent increases the rigidity of the assembled back section, the back section is divided into two portions that can be disengaged to allow access for insertion of the hard bolts into the armrests. This two-piece back section is more costly to produce than a conventional sofa back section.
It would be advantageous to have a frame assembly for RTA modular furniture that allows the furniture to be quickly assembled and yet has relatively rigid construction without sacrificing aesthetic appeal. It would be further advantageous if the backrest of the furniture could be rigidly secured to the base of the furniture piece using the frame assembly without undue visible alterations in the appearance of the backrest or base of the furniture piece. It would be further advantageous if the frame assembly were adaptable to different aesthetic variations of furniture and different types of furniture, such as sleeper sofas.
The present invention addresses the above needs and achieves other advantages by providing a frame assembly for securing a plurality of modular sofa parts together into the sofa frame by producing a positive fit between one, or more, of the modular sofa parts. More particularly, the frame assembly includes a pair of tapered members attached to opposing sides of a backrest sofa part and a pair of receptacles attached to respective ones of a pair of rails, which are in turn attached to a pair of armrests. The backrest is connected between, and to, the armrests and rails by inserting each of the tapered members into a tapered slot defined by each respective receptacle. The tapered shape of the tapered members and slots produces the positive fit that has two directional components to prevent front-to-back rocking, and side-to-side rocking, of the backrest. The positive fit between each tapered member and receptacle is further strengthened using a pair of overlapping securing members each connected to a respective one of the tapered member and receptacle. The securing members may be transfixed with a hand bolt which is tightened to draw the tapered member further into the tapered slot. Further, the rails each define a plurality of holes configured to accept one of a pair of spaced drop-in supports of a spring unit, a sleeper unit, and a futon unit allowing the sofa frame to be easily upgraded or adapted as desired by the user.
In one embodiment, the frame assembly secures a plurality of modular sofa parts together into a sofa frame. The modular sofa parts include a pair of base walls, a pair of armrests and a backrest. The frame assembly includes a pair of elongate rails, a pair of receptacles and a pair of tapered members. Each of the elongate rails includes a pair of spaced bracket portions configured for attachment to a common one of the armrests. Each spaced bracket portion is further configured for attachment to a respective one of the pair of base walls. Each receptacle has a wall structure defining a tapered slot and each receptacle is attached to a respective one of the pair of elongate rails. The pair of tapered members are configured for attachment to the backrest. Each tapered member has at least one tapered outer surface receivable by a corresponding one of the pair of receptacles in a positive fit.
The frame assembly can be assembled by spacing apart the pair of elongate rails and attaching the bracket portions of the elongate rails to their respective base walls so as to space apart the base walls and secure the base walls to the elongate members. The pair of tapered members are also spaced apart and attached to the backrest. Once attached to the backrest, the tapered members are inserted into the receptacles so that each of the tapered outer surfaces is engaged with a respective tapered slot in a positive fit which rigidifies the sofa frame.
In another aspect, the pair of tapered members each include a second tapered outer surface so that the positive fit is configured to extend in multiple directions. The tapered slot defined by each wall structure may have a flattened triangular shape and the tapered outer surface of each tapered member also has a flattened triangular shape which configures the positive fit to extend in the first direction. The flattened triangular shape may also have a trapezoidal cross-section that forms a second pair of tapered surfaces which configures the positive fit to extend in a second direction. The first and second directions correspond to front-to-back, and side-to-side, motions relative to the sofa frame.
In yet another aspect, the walls structure defining the tapered slot includes at least three inner surfaces. A first inner surface has a triangular shape with a pair of vertical edges. A pair of second inner surfaces are spaced apart across the first inner surface and extend inwards from the vertical edges of the triangular shape. Each tapered member may include three of the tapered surfaces wherein each tapered surface is congruently shaped to a respective one of the at least three inner surfaces so that the positive fit extends in at least two directions.
In another embodiment, the pair of elongate rails each include a first and second overlapping channels that slidingly interfit. The first bracket is attached to the first channel and the second bracket is attached to the second channel allowing spacing between the bracket portions to be adjusted for differently sized armrests.
In another aspect, each receptacle further includes a first securing member and each tapered member includes a second securing member. The first and second securing members are configured to overlap and receive a fastener so that each tapered member can be secured to the corresponding one of the receptacles. The first securing member may be positioned on a bottom portion of the tapered member. The second securing member may be positioned on a bottom portion of the receptacle so that tightening the fastener draws the tapered member further into the receptacle thereby increasing the positive fit.
In another embodiment, each of the pair of elongate rails are configured for attachment of a pair of drop-in unit supports. The elongate rails define a plurality of holes configured to receive fasteners for attaching a respective one of the drop-in unit supports. Preferably, the drop-in unit supports support any combination of a futon, a sleeper unit or a spring unit.
In yet another embodiment, the present invention includes a positive fit assembly for rigidly securing two modular furniture pieces together in a positive fit. The positive fit assembly includes a receptacle and a tapered member. The receptacle is configured for attachment to one of the modular furniture pieces and has a triangular first wall with a pair of vertical edges, a pair of second walls and a securing member. The pair of second walls are spaced apart across the triangular first wall and each extends inwards from a respective one of the pair of vertical edges of the triangular first wall. The triangular first wall and the second walls define a tapered slot and the securing member extends laterally from the triangular first wall.
The tapered member is configured for attachment to another one of the modular furniture pieces and has a triangular first surface with a pair of vertical edges, a pair of second surfaces and a second securing member. The pair of second surfaces each extend outwardly from a respective one of the pair of vertical edges and the securing member extends laterally from the triangular first surface.
The receptacle can be attached to its modular furniture piece. The tapered member can be attached to the other one of the furniture pieces. The two furniture pieces are connected by sliding the tapered member into the tapered slot defined by the walls of the receptacle until the pair of second surfaces are flush with the pair of second walls.
The present invention has several advantages. The modular sofa parts are firmly interconnected by the frame assembly into the sofa frame, while still being easy to assemble and disassemble without tools due to the use of several hand bolts and the positive fit of the tapered members and receptacles. The modular assembly further speeds up the assembly at the plant, showroom or home and can be performed by a single person. The modular sofa parts are more efficiently shipped due to more efficient packing of the parts. The positive fit of the tapered members into the receptacles, aided by the securing members, increases stability of the backrest in at least two directions. The securing members are positioned so that they can be tightened before drop-in of the drop-in unit and do not require an unsightly access panel or hole in the upholstery. The sofa frame, and frame assembly, are easily adapted for use with a plurality of drop-in units, including a spring unit, a sleeper unit and a futon unit.